1. Field of the Invention
The present invention relates to a radiation mask for the lithographic production of patterns. The radiation mask includes a carrier layer mounted in a support frame. The carrier layer defines a structure corresponding to the pattern to be created.
2. Description of the Prior Art
A radiation mask of the above-described type is used particularly for the X-ray lithographic or ionic lithographic production of semiconductor modules and semiconductor components and of optical grids.
Radiation masks for the X-ray lithographic production of patterns are known from German Offenlegungsschrift No. 32 32 499 and German Offenlegungsschrift No. 34 27 449. These masks include a radiation permeable carrier layer mounted in a support frame. The carrier layer has a radiation absorbing structure which corresponds to the pattern to be created.
A radiation mask of the same type for X-ray lithography or ionic lithography is described in German Offenlegungsschrift No. 31 50 056. The support frame for the radiation permeable carrier layer of the mask has markings for the optical alignment of the radiation mask relative to the semiconductor substrate to be irradiated.
Since a high resolution of the pattern to be created can be achieved particularly by means of X-ray lithography, an extremely high dimensional accuracy of the structure of the radiation mask corresponding to the pattern to be created is absolutely required.
In the manufacture and the use of such a radiation mask, variable stress components occur for various reasons, for example, due to temperature-related loading of the carrier layer with the structure during irradiation or due to deformations of the carrier layer with the structure caused by improper fastening in the support frame. These variable stress components may lead to non-reproducible lateral distortions of the carrier layer, so that the dimensional accuracy of the radiation mask is no longer ensured.
German Offenlegungsschrift No. 34 25 063 discloses a radiation mask for X-ray lithography in which such lateral mechanical distortions are avoided by means of a stress-compensated carrier layer. This carrier layer is a silicon layer doped with two different materials to achieve the stress compensation. However, this type of stress compensation requires specific materials. In addition, a radiation mask with this type of stress compensation is difficult to manufacture.
It is, therefore, the primary object of the present invention to provide a radiation mask of the above-described type in which the dimensional accuracy of the structure is maintained during the occurrence of stress components.